Running the program

That's about it! Let's go ahead and run our program. Go to Debug > Start Without Debugging or do Ctrl + F5. Give it a second to build and then you should get your results:

Figure 3.2: The debug Window

It says the sum is 12 and the average is 2. These are simple values, so you can just check them on a calculator. Go ahead and check them. Add them up and make sure that the sum is 12. Then, you can average them out. We have six values in our array, so 12 divided by 6 is 2. This is the average.

When you design this kind of a program, first you try to keep your sample array small and make sure that you double-check your math on a calculator. That's a good indicator that the code is sound. This is it for this simple example of using the out keyword in C# 7. Here's the full program code for your reference:

using static System.Console; //needed for getting WriteLine into our code 
 
class Program 
{ 
    static void Summarize(double[] values, out double sum, out double 
    average...